Diesel engine fuel pump



"Ma 12, 1942. C L 2,282,562

DIESEL ENGINE FUEL PUMP I Filed Nov. 7, 1939 72 as fi 24 7g I Z6 I 18 aINVENTOR ATTO R N EYS Patented May 12, 1942 UNITED STATES PATENT OFFICEDIESEL ENGINE FUEL PUMP Wheeler J. Cole, Ann Arbor, Mich. ApplicationNovember, 7, 1939, Serial No. 383,337

7 Claims.

My invention relates to internal combustion engines of the Diesel type,and has among its objects and advantages the provision of an improvedfuel injection pump.

Fuel injection pumps such as are employed in Diesel engines, forexample, are subjected to enormous pressures. Because of high pressuresrequired in such pumps, considerable difllculty has been heretoforeencountered in precisely shaping the plungers, barrels, etc., torequired specifications. It is common practice to hand lap such parts totheir correct relative sizes, and such work entails considerable timeand expense.

Accordingly, an object of my invention is to provide a fuel injectionpump embodying novel means designed to effectively hold the highpressures to which such pumps are subjected. More specifically, I makeuse of a plunger and barrel construction provided with sealing ringscapable of holding the necessary high pressures, thus permitting theplunger and barrel parts to be constructed with machine tolerances,thereby eliminating the time and cost elements incident to hand lappingcommon in the art. I provide novel means for retaining the sealing ringsand in which said means are so devised as to permit assembly of therings without enlarging their diameters preparatory to being slippedinto position, thereby eliminating any danger of breakage.

A further object is to provide a fuel injection pump embodying a novelfuel metering feature so that the amount of fuel delivered to the enginemay be varied from maximum to minimum in accordance with variations inengine speed. The metering device is designed so as to be operablethrough the medium of an engine driven governor.

In the accompanying drawing:

Figure 1 is a sectional view of a fuel injection pump in accordance withmy invention;

Figure 2 is an enlarged sectional view of a portion of the structure ofFigure 1; and

Figure 3 is a sectional -view along the line 33 of Figure 1.

In the embodiment selected to illustrate my invention, I make use of acasing [8 having a base l2 within which is J'ournaled the usualengine-driven shaft 14 upon which I mount a cam I6. Casing l8 includes abore [8 provided with an intersecting bore 28 within which I rotatablymount a shaft 22 operatively connected with a governor (not shown) to berotated in accordance with the speed of the engine. Such governors arewell known in the art and need not be described in detail.

Shaft 22 includes a longitudinal recess 24 for the reception of a lug 28carried by a fuel metering sleeve 28 adapted to be reciprocatedlongitudinally of the bore l8 through rotary motion of the governorrotated shaft 22. Sleeve 28 is of considerably less outside diameterthan the bore l8 to provide a reservoir 38 for fuel. The upper end ofthe metering sleeve 28 slidably embraces an upper plunger 32 which isbored at 34 for the passage of fuel to the engine, and is provided witha threaded extension 36 for connection with an injection or deliverypipe (not shown).

Bore I8 is provided with internal threads 38 for connection with athreaded sleeve 48 having a nut 42 positioned adjacent the end 44 of thecasing l8. Between the nut 42 and the end 44 I place a sealing gasket48. The inner bore 48 of the sleeve 48 is slightly larger in diameterthan the outside diameter of the sleeve 28 to permit free relativemovement of the latter.

Fig. 1 illustrates the lower end of the metering sleeve 28 as embracingthe upper end of the lower plunger 58, which has its lower end providedwith a head 52 arranged in operative relation with the cam l6. Thus, theplunger 58 will be reciprocated through rotary motion of thcam I6. Borel8 communicates with a larger axial bore 54 through which the greaterpart of the lower plunger extends, and in which I position a sea1- ingring 56 which embraces the outer face of the metering sleeve 28.Adjacent the sealing ring 58 I position a sealing gland 58 which alsoembraces the metering sleeve. Between the sealing gland 58 and thebottom 88 of a cup 82 I interpose a compression'spring 84. Cup 62 isslidable in the bore 54, and the bottom 68 of the cup is urged againstthe head 52 on the plunger 58 by reason of thecompression spring 64.

The reservoir '38 is supplied with fuel from a pipe leading to a fuelsupply (not shown), and the metering sleeve 28 is provided with aplurality of ports 66 which place the reservoir 38 in communication withthe bore 88 of the metering sleeve. Movement of the metering sleeve 28is controlled through rotation of the .shaft 22. Thus, the position ofthe ports '66 is determined by the speed of the governor, which in turnis controlled by the engine. Fig. 1 illustrates the metering sleeve 28in a lowered position, and the plunger 58 is in its retracted position,with the ports 86 at this time located above the upper end of theplunger 58. Fig. 2 illustrates the position of the metering sleeve 28 inits upper extreme position and with the plunger 50 correspondinglyelevated.

According to the illustration of Fig. 1, upward movement of the plunger50 by the cam I 6 will cover the ports 66 so that the fuel trappedinside the metering sleeve between the plungers 32 and 50 will be forcedto the engine through the bore 34. Elevation of the metering sleeve 28,in response to increased engine speed, brings the ports 66 closer to theplunger 32 so that the plunger 50 must travel upwardly a greaterdistance before it will cover the ports 68. In other words, elevation ofthe metering sleeve: 28 increases the distance of the ports 66 from theend of th lunger 50 when in its maximum lowered position so that theplunger 50 will deliver a smaller quantity of fuel to the engine afterit closes the ports 66. Thus, the amount of fuel delivered to the engineis effectively controlled through the medium of the metering sleeve 28which is responsive to engine speed.

The governor will, of course, be equipped with the usual manual controlso that the engine may be stopped through rotation of the shaft 22 forshifting the sleeve 28 to the position of Fig 2, at which time fuel willflow through the ports 66 rather than through the bore 34.

Plunger 32 is provided with a series of sealing rings I0, while theplunger 50 is provided with a series of sealing rings l2. 2, plunger 32is fashioned with a shank I4 upon which flanged sleeves I6 and I8 aremounted, with the sleeve I8 having threaded connection with the shankI4, as at 80. One of the sealing rings 10 is housed between the flangeof the sleeve I6 and the shoulder 82 of the plunger 32, while the othersealing ring I is housed between the two flanges of the flanged sleevesI0 and I8. Sleeve 18 may be provided with bores 84 for connection with atool such as a spanner wrench to facilitate tightening of the parts.While the flanged sleeves I6 and I8 may be turned down tightly to haverelative fixed connection with the shank I4, the flanges of the sleevesand the shoulder 82 are so spaced as to loosely support the sealingrings in the necessary degree so that the rings may have proper sealingrelation with the wall of the bore 68.

Plunger 50 includes a threaded shank 86 upon which I mount flangedsleeves 88, 80 and 92. Sealing rings I2 are assembled with the flangedsleeves 88, 90 and 92 in the same manner as the sealing rings I2 areassembled with the flanged sleeves I6 and I8. Flanged sleeve 82 hasthreaded connection with the shank 8B and the sleeve is provided withbores 94 for connection with a spanner wrench.

Bore 34 communicates with a larger diameter bore 96 terminating in avalve seat 98. Bore 34 is normally closed by a ball valve I00 biasedagainst the seat 98 by a compression spring I02 with a pressure somewhatin excess of the supply pressure of the fuel. A sleeve I04 has threadedconnection at I06 with the extension 80 to constitute an abutment forthe compression spring I02, and the sleeve includes a fuel passage I08.Compression spring I02 maintains the ball valve I00 upon its seat 88until the pressure exerted by the fuel trapped in the metering sleeve 28increases substantially above that at which the fuel is supplied to themetering sleeve.

The sealing rings associated with the two plungers cooperate with themetering sleeve 20 in such manner as to effectively hold the workingpressure. The sealing rings are easily assem- Referring to Fig.

bled with their retaining parts, and these parts are so fashioned as topermit assembly of the rings without enlarging their diameters. Thus,the sealing rings permit the use of a metering sleeve and associatedplungers having machine tolerances so as to completely eliminate thenecessity of hand lapping, thus greatly reducing the manufacturing costof such parts, in addition to providing a plunger and barrel structurecapable of holding the high pressures necessary in fuel injection pumpsof this type.

While I have illustrated a single plunger unit, it will be understoodthat my invention is equally well adapted to multiple plunger units.

Having thus described certain embodiments of my invention in detail, itis, of course, understood that I do not desire to limit the scopethereof to the exact details set forth except insofar as those detailsmay be defined in the appended claims.

I claim:

1. A fuel injection pump comprising a casing having a fuel chamber; afixed plunger having a fuel outlet passage; a reciprocatory fuelinjection plunger arranged coaxially with the fixed plunger; anadjustable fuel metering sleeve slidable axially on said first plungerand slidably receiving said reciprocatory plunger; a sealing meansextending circumferentially about said sleeve and comprising a wallportion of said fuel chamber; said fixed and reciprocatory plungersbeing axially spaced and said sleeve having a port placing the interiorof the sleeve between the fixed and reciprocatory plungers incommunication with said chamber; said reciprocatory plunger closing saidport upon a predetermined fuel injection stroke travel relatively to thesleeve to force fuel trapped in the sleeve through said fuel outletpassage; and means for shifting said sleeve relatively and axially ofsaid fixed and reciprocatory plungers to vary the amount of fuel trappedin said sleeve.

7 2. A fuel injection pump comprising a casing having a fuel chamber; afixed plunger having a fuel outlet passage; a reciprocatory fuelinjection plunger arranged coaxially with the fixed plunger; anadjustable fuel metering sleeve slidable axially on said first plungerand slidably receiving said reciprocatory plunger; a sealing meansextending circumferentially about said sleeve and comprising a wallportion of said fuel chamber; said fixed and reciprocatory plungersbeing axially spaced and said sleeve having a port placing the interiorof the sleeve between the fixed and reciprocatory plungers incommunication with said chamber; said reciprocatory plunger closing saidport upon a predetermined fuel injection stroke travel relatively to thesleeve to force fuel trapped in the sleeve through said fuel outletpassage; and a rotary means journaled in said casing and operativelyconnected with said sleeve for shifting the sleeve relatively andaxially of said fixed fand reciprocatory plungers to vary the amount offuel trapped in said-sleeve.

3. A fuel injection pump comprising a casing having a fuel chamber; afixed plunger having a fuel outlet passage; a reciprocatory fuelinjection plunger arranged coaxially with the fixed plunger; anadjustable fuel metering sleeve slidable axially on said first plungerand slidably receiving said reciprocatory plunger; a sealing meansextending circumferentially about said sleeve and comprising a wallportion of said fuel chamber; said fixed and reciprocatory plungersbeing axially spaced and said sleeve having a port placing the interiorof the sleeve between the fixed and reciprocatory plungers incommunication with said chamber; said reciprocatory plunger closing saidport upon a predetermined fuel injection stroke travel relatively to thesleeve to force fuel trapped in the sleeve through said fuel outletpassage; a rotatable control shaft journaled in said casing; and anoperating connection between said shaft and the sleeve for shifting saidsleeve relatively and axially of said fixed and reciprocatory plungersthrough rotation of the shaft to vary the amount of fuel trapped in saidsleeve.

4. A fuel injection pump comprising a casing having a fuel chamber; afixed plunger having a fuel outlet passage; a reciprocatory fuelinjection plunger arranged coaxially with the fixed plunger; anadjustable fuel metering sleeve slidable axially on said first plungerand slidably receiving said reciprocatory plunger; a sealing meansextending circumferentially about said sleeve and comprising a wallportion of said fuel chamber; said fixed and reciprocatory plungersbeing axially spaced and said sleeve having a port placing the interiorof the sleeve between the fixed and reciprocatory plungers incommunication with said chamber; said reciprocatory plunger closing saidport upon a predetermined fuel injection stroke travel relatively to thesleeve to force fuel trapped in the sleeve through said fuel outletpassage; a rotatable control shaft joumaled in said casing and having arecess; and a projection on said sleeve fitting in the recess forshifting said sleeve relatively and axially of said fixed andreciprocatory plungers through rotation of the shaft to vary the amountof fuel trapped in said sleeve.

5. A fuel injection pump comprising a casing having a fuel chamber; afixed plunger having a fuel outlet passage; a reciprocatory fuelinjection plunger arranged coaxially with the fixed plunger; anadjustable fuel metering sleeve slidable axially on said first plungerand slidably receiving said reciprocatory plunger; said fixed andreciprocatory plungers being axially spaced and said sleeve having aport placing the interior of the sleeve between the fixed andreciprocatory plungers in communication with said chamber; saidreciprocatory plunger closing said port upon a predetermined fuelinjection stroke travel relatively to the sleeve to force fuel trappedin the sleeve through said fuel outlet passage; means for shifting saidsleeve relatively and axially of said fixed and reciprocatory plungersto vary the amount of fuel trapped in said sleeve; said reciprocatoryplunger being guided by said sleeve; and sealing means defining in partsaid fuel chamber for guiding said sleeve.

6. A fuel injection pump comprising a casing having a fuel chamber; afixed plunger having a fuel outlet passage; a reciprocatory fuelinjection plunger arranged coaxially with the fixed plunger; anadjustable fuel metering sleeve slidable axially on said first plungerand slidably receiving said reciprocatory plunger; said fixed andreciprocatory plungers being axially spaced and said sleeve having aport placing the interior of the sleeve between the fixed andreciprocatory plungers in communication with said chamber; said recprocatory plunger closing said port upon a predetermined fuel injectionstroke travel relatively to the sleeve to force fuel trapped in thesleeve through said fuel outlet passage; means for shifting said sleeverelatively and axially of said fixed and reciprocatory plungers to varythe amount of fuel trapped in said sleeve; said reciprocatory plungerbeing guided by said sleeve; a shoulder in said casing; and a sealingmeans pressed against said shoulder for guiding said sleeve and definingin part said chamber.

7. A fuel injection pump comprising a casing having a first bore and acoaxial second bore of larger diameter providing a shoulder at themeeting ends of the first and second bores; said first bore comprising afuelreservoir; a fuel metering sleeve arranged axially of the first andsecond bores; a closure means for one end of said first bore and havinga fixed plunger provided with an axial fuel outlet; said sleeve havingone end slidably embracing said fixed plunger; a reciprocatory fuelinjection plunger slidable in said sleeve; a sealing means inside saidsecond bore adjacent said shoulder and embracing said metering sleeve toguide the latter and to close the other end of said first bore; saidfixed and reciprocatory plungers being axially spaced and said sleevehaving a port placing the interior of the sleeve between the fixed andreciprocatory plungers in communication with said reservoir; said fuelinjection plunger being provided with a cup opening in the direction ofsaid sealing means and slidably guided inside said second bore;resilient means acting on said cup and said sealing means for pressingthe latter against said shoulder; said reciprocatory plunger closingsaid port upon a predetermined fuel injection stroke travel to forcefuel trapped in the sleeve through said fuel outlet passage; and rotarymeans operatively connected with said sleeve for adjusting the latterrelatively and axially of said fixed and reciprocatory plungers to varythe amount of fuel trapped in said sleeve.

WHEELER J. COLE.

